Citations

Abstract Purpose: Investigate the utility of patient-specific spatial predictions of tumor cell density from a bio-mathematical model. Introduction: Glioblastomas (GBMs) are the most malignant of all primary brain tumors. While it is known there is always a non-detectable portion of the tumor, current techniques of monitoring GBM progression, imaging and initial histological assessment, are not able to reliably estimate the tumor invasion past the enhancing region on T2-Weighted (T2W) imaging. Over the last two decades, a large effort has been made to create a simple patient-specific mathematical model of gliomas. The resulting model, referred to as the Proliferation-Invasion (PI) model, is based on two key parameters, the net growth rate, ρ, and the dispersal coefficient, D. In this model, the ratio of D/ρ is related to degree of invasion and the product D*ρ, is related to the speed of growth. The intuitive understanding provided by this model has been able to provide patient-specific understanding of disease kinetics enabling prediction of outcomes following surgical resection, radiation and the development of a prognostic response metric. Previous literature utilizing this model has been based on the assumption that what is seen on the pretreatment T1-Weighted contrast-enhanced (T1Gd) and T2W, images correspond to an 80% and 16% tumor cell density threshold respectively. This assumption allows for an estimate of D/ρ from a single time point of imaging. While these values were based on extensive experience, for ethical and technical reasons, they have never been rigorously investigated histologically. Recent technological advances have made it possible for surgeons to use an MRI to guide the acquisition of tissue making it possible to know with a good degree of accuracy where on the MR image the histological specimen comes from. Methods: Model Calibration : To estimate D/ρ for each patient, we assume abnormalities on the T1Gd and T2W images correspond to an 80% and 16% tumor cell density threshold respectively. We then utilize a Bayesian calibration approach based on adaptive grid refinement while holding the velocity constant to find the most likely value of D/ρ to match the observed radial measurements. Three-Dimensional Density Maps : Given a gray/white segmentation and an estimate for D/ρ, we can build a tumor cell density prediction in the patient's anatomy using the Eikonal equations and the modified Fast Marching Method (FMM) algorithm presented by Konukoglu et al. Patient Cohort : Eighteen patients were recruited with clinically suspected GBM undergoing preoperative stereotactic MRI for surgical resection with IRB approval Barrow Neurological Institute and Mayo Clinic in Arizona. Surgical Biopsy : Pre-operative conventional MRI, including T1Gd and T2W, was utilized to guide stereotactic biopsies. An average of 5–6 tissue specimens were acquired from each tumor by using stereotactic surgical localization, following the smallest possible diameter craniotomies to minimize brain shift. Histological Analysis : 4 μm tissue sections were stained with hematoxylin and eosin (H&E) for neuropathology review. H&E slides were reviewed by a neuropathologist. The percent tumor nuclei in the field was estimated. Results and Conclusion: Our analysis showed that the intuitive ordering of diffuse to nodular tumor profiles from the PI model is consistent with the histologic data. Further, utilizing the histologic data, limitations to a universal threshold cutoff of the T2/FLAIR region are specified and a better threshold cutoff value is suggested. We hope that this paper will lead to more studies of this kind resulting in more accurate ways to predict the spatial distribution of GBM tumor cells from medical imaging. Such advances could revolutionize surgical procedures and radiation therapy and may enable additional insights into tumor kinetic differences meaningful for treatment. Citation Format: Andrea Hawkins-Daarud, Lauren DeGirolamo, Joshua Jacobs, Kamala Clark-Swanson, Jennifer M. Eschbacher, Kris A. Smith, Peter Nakaji, Leslie C. Baxter, John P. Karis, Teresa Wu, J. Ross Mitchell, Jing Li, Leland Hu, Kristin R. Swanson. Histologic evidence for a bio-mathematical model of glioblastoma invasion. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr A08.

Abstract Stool DNA testing has emerged as a sensitive, noninvasive option for colorectal cancer (CRC) screening. A multi-target stool DNA test (MT-sDNA) has recently become available in the U.S. as the first FDA-approved molecular-based cancer screening test (“Cologuard” (Exact Sciences)). It is also approved by the Centers for Medicare & Medicaid Services and is incorporated into new screening guidelines by ACS, USPSTF, NCCN, and various other societies. Stool DNA tests target signature genetic and/or epigenetic markers that continuously exfoliate from CRC and its precursors. In early comparison studies (Clin Gastroenterol Hepatol. 2012;10:272), stool assay of exfoliated molecular markers proved to be more sensitive than DNA testing on paired plasma for detection of colorectal neoplasia, and differences were most striking with early stage CRC and precancers. Such findings suggest that the mechanism of luminal exfoliation into stool may provide a biological advantage in early detection as it appears to occur sooner in the oncologic cascade than does vascular invasion into the circulation. Average-Risk CRC Screening: The performance of the optimized MT-sDNA test (which assays a panel of 2 methylated genes, mutant KRAS, and hemoglobin) has been evaluated in multiple clinical studies. Case-control studies showed that CRC and precancers at greatest risk for progression could be detected with high sensitivity, that detection was unaffected by tumor stage or site within the colon, and that sensitivity for polyps increased in proportion to lesion size (Gastroenterology 2012;142:248, Clin Gastroenterol Hepatol 2013;11:1313). In subsequent cross-sectional validation studies from the screening setting (NEJM 2014; 370:1287, Mayo Clin Proc 2016;91:61), MT-sDNA achieved sensitivities for CRC of 92-100% at specificities (based on a denominator of patients with normal colonoscopy) of 90-93%; sensitivities for adenomatous or serrated polyps >1cm, >2cm, and >3cm were respectively 42-43%, 60-66%, and 67-82%. Neoplasm detection by MT-sDNA was significantly higher than by fecal blood testing in these studies. Cumulative or “program” performance of MT-sDNA has been modeled. At the recommended testing frequency of every 3 years, MT-sDNA exhibits a higher benefit-to-risk ratio than the other endorsed CRC screening approaches and generates the fewest number of colonoscopies (i.e., highest program specificity) over a screening lifetime (JAMA 2016;315:2564). Furthermore, because polyps are slow-growing, it has been estimated that the program sensitivity of MT-sDNA for a cohort of advanced adenomas may exceed 90% by the 2nd or 3rd screening rounds (Dig Dis Sci 2015;60:623). Thus, over a lifetime of screening, regular use of MT-sDNA every 3 years has the potential to compare favorably with colonoscopy performed every 10 years in the detection of both CRC and those polyps at greatest risk for progression. In the screening setting, effective neoplasm detection is based not only on test sensitivity but on patient compliance and test access as well. The user-friendly features of MT-sDNA have potential to enhance screening participation rates, and these include noninvasiveness, operator-independence, and avoidance of bowel preparation and diet/medication restrictions. Furthermore, unlike with colonoscopy which requires an average of two missed work days, MT-sDNA can be done from home with no missed work and access by mail is virtually unlimited. Early outcomes with MT-sDNA indicate that >40% of patients tested had not undergone CRC screening previously (based on questionnaire reports to Exact Sciences from first 100,000 test users). Further studies are needed to determine the uptake of this new test and its impact on CRC screening participation and long-term outcomes. Dysplasia Surveillance in Inflammatory Bowel Disease (IBD): Patients with IBD are at increased risk for CRC. Although IBD patients are currently advised to undergo surveillance colonoscopy annually or every 2 years, only half comply with this rigorous regime. Complementary approaches are needed. In early case-control studies (APT 2013;37:546, Gastroenterology 2016;150:S48), stool DNA testing targeting a panel of informative methylated gene markers detected 90-100% of CRC and high grade dysplasia in IBD patients using colonoscopy and surgery as reference standards. Modeling suggests that stool DNA testing every 1-2 years followed by chromo-endoscopy if positive is more cost-effective than either chromo-endoscopy or white-light colonoscopy alone (Kisiel et al. Clin Gastroenterol Hepatol (in press)). A multi-center study of stool DNA for IBD surveillance is underway. Extending Detection to Upper GI Neoplasms: Together, upper GI cancers account for roughly twice as many deaths as CRC does. Yet, they remain largely unscreened due, in part, to relatively lower single site prevalence and lack of cost-effective screening tools. Since all mucosal-based GI neoplasms exfoliate contents into a common excretory conduit, molecular stool testing allows the re-imagination of the GI tract as a single screen-able organ. Perceived in this way, it is the aggregate prevalence that counts and the value of a single screening intervention could theoretically be extended beyond the colon. While preliminary data suggest that tumors at all GI tract sites can be detected by stool DNA testing (Gastroenterology 2009; 136:2068), much technical optimization and substantial clinical testing are required to evaluate the feasibility and practicality of this intriguing approach. In summary, stool DNA testing has potential to favorably affect detection accuracy, patient compliance, and access with general CRC screening. Early data suggest that this approach may have value as a complement to colonoscopy in the surveillance of IBD. And, potential future applications of stool DNA testing could include universal GI cancer screening. Citation Format: David A. Ahlquist. Stool DNA detection of colorectal neoplasia. [abstract]. In: Proceedings of the AACR Special Conference on Colorectal Cancer: From Initiation to Outcomes; 2016 Sep 17-20; Tampa, FL. Philadelphia (PA): AACR; Cancer Res 2017;77(3 Suppl):Abstract nr IA13.

Abstract Ovarian cancer is the most lethal gynecologic cancer and the fifth most common cause of cancer death among women in the United States. Although there have been incremental improvements in progression free survival over the last several decades from advances in surgical technique and combination-chemotherapy strategies, overall survival has essentially remained unchanged. Although novel therapeutics have the potential to impact overall survival and lead to more cures, drug development in this area has been limited by the availability of clinically relevant models that recapitulate the molecular and phenotypic characteristics of primary ovarian cancers. To overcome this barrier, we have developed primary patient derived xenograft (PDX) models from every consenting patient having primary debulking surgery at Mayo Clinic since 2010 (>550 unique patients). Fresh tissues are minced and injected intraperitoneally into severe combined immunodeficient (SCID) mice without enzymatic digestion or surgical implantation. The patient-to-mouse time is typically <1.5 hours and the engraftment rate is 73%. Ovarian PDX models have demonstrated their utility as patient surrogates. The histologic diversity is representative of the population from which they are derived with high-grade serous comprising most of the models. However, the ovarian PDX bank also includes less-common subtypes, such as clear cell, mucinous, and carcinosarcoma. Histologic and genomic fidelity is maintained within early-passage tumors. Moreover, the patient's clinical response to carboplatin and paclitaxel (a standard front-line therapy for ovarian cancer) demonstrates high correlation to the matched PDX tumor response in vivo, supporting their relevance as patient surrogates. The models have been used for preclinical drug development and biomarker validation. One example is the correlation between PARPi response in PDXs and their homologous recombination deficiency (HRD) score. All models with a low HRD score, <42, failed to respond to PARP inhibition while models with a high HRD score showed enrichment for response to a PARPi. Ovarian PDXs are also being used to direct patient care in a clinical trial setting at all three Mayo Clinic sites (MN, FL, and AZ). Tumors are collected at the time of debulking surgery for heterotransplantation. Subsequent xenografts are treated with standard first-line chemotherapy, similar to their matched patient in the clinic, and then PDXs are treated with standard ovarian cancer second-line therapies: liposomal doxorubicin, topotecan, gemcitabine, and paclitaxel. When patients develop platinum-resistant recurrent cancer, the chemotherapy response in the PDX is used to direct therapy in the clinic. Many challenges continue for ovarian cancer PDX models. The use of immunocompromised mice limits the ability to study the involvement of immunity in chemotherapy responsiveness. In addition, these models are not ideal for testing novel immunotherapies, such as the immune check point inhibitors. Further work to overcome these and other limitations are needed. Citation Format: S. John Weroha. Ovatars in preclinical drug development and clinical trial for ovarian cancer patients. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr IA11.

Abstract Mutations in the EGFR gene or transcript fusion involving EML4-ALK result in oncogenic activation of these oncogenes driving lung adenocarcinoma growth in tumors carrying such an alteration. For lung adenocarcinoma with these genetic changes, small-molecule tyrosine kinase inhibitors have been highly effective at reducing tumor burden and improve the outcome of the patients. Unfortunately, drug resistance eventually develops in these tumors and challenges remain in controlling lung cancer recurrence after targeted therapy. To overcome recurrence, we initiated a prove-of-principle study to evaluate the feasibility of an integrated strategy utilizing genomic profiles of the tumor and patient-specific tumor xenografts derived (PDX) from biopsies for ex vivo evaluation of antitumor drugs to help guide personalized treatment of lung cancer in patients who have developed resistance to targeted therapy drugs. Our study has three main objectives. 1) Use tumor biopsies obtained at the time of recurrence for oncogene mutation and RNAseq analyses to identify molecular changes in oncogenes and gene pathways that can be potentially targeted. 2) Evaluate drug efficacy and optimize personalized therapy for each patient using PDX models. 3) Assess clinical feasibility and our experience using integrated approaches for lung cancer patients who failed targeted therapy. This study was approved by the Mayo Clinic Institutional Review Board (IRB) and utilizes both clinical and research biopsies. A dedicated nurse study coordinator reviews clinical patient list and history on weekly basis and informs the study team of each potential candidate patient. A total of 30 patients having ALK positive lung cancers have been identified and followed up from nearly 500 potentially ALK positive cases between April 2014 to Sept. 2015. Most patients were never smokers but six were former smokers and two were current smokers. Age at diagnoses ranged from 27-78 years (median = 61). Seven patients (23%) were 45 years or younger at the time of diagnosis. A total of 22 patients are currently being treated with crizotinib while eight are on ceritinib or alectinib. For each biopsy, tumor tissues are obtained using a 20 gauge needle, transferred on ice in preserving media and implanted within one hour into 6-8 week old NOD/SCID mice. Many patients have been on treatment for 2-3 years with stable disease so they do not require biopsy. Using a similar strategy, we also obtained biopsies from patients with EGFR gene mutations in their tumors and have progressed while on targeted therapy. A total of seven cases have been implanted. We will report our experiences in patient selection, clinical follow up, patient consent, PDX development, time from biopsy to tumor establishment, and the results of molecular analyses. Our study enabled us to gain new insights regarding the molecular changes associated with recurring tumors after they have failed targeted therapy as well as clinical experiences on how to utilize state-of-the art approaches and comprehensive genomic information to further improve cancer patient care upon disease progression. Acknowledgements: This work is supported in part by the Hillsberg Award from the National Foundation for Cancer Research and by the Biomarker Discovery Program at the Mayo Clinic Center for Individualized Medicine. Citation Format: Jin Jen, Aaron Mansfield, Patrick W. Eiken, Shawn Stoddard, Karlyn Pierson, Xiaonan Hou, Hong Zheng Ren, Julian Molina, Joanne Yi, Ping Yang. Integrated Approaches to Treating Lung Adenocarcinoma Resistant to Targeted Therapy. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B34.

Abstract Clinical data indicate that certain regions within glioblastoma (GBM) have a relatively intact blood-brain barrier (BBB), but controversy surrounds whether associated heterogeneous delivery may limit efficacy for otherwise highly active drugs with poor brain distribution. In this study, the efficacy of molecularly targeted therapies was compared in relevant GBM patient-derived xenograft (PDX) models grown either as heterotopic or orthotopic tumors. The impact of further disrupting BBB integrity in non-responsive orthotopic tumors was evaluated by over-expressing vascular endothelial growth factor (VEGF) and measuring drug distribution by matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI). The brain:plasma ratio for five targeted agents was determined by LC-MSMS and treatment efficacy was evaluated in target-relevant GBM PDX lines: erlotinib (brain:plasma = 0.02 ± 0.02; efficacy tested in GBM6), palbociclib (brain:plasma = 0.06; efficacy tested in GBM22), AZD1775 (brain:plasma = 0.05; efficacy tested in GBM22), SAR405838 (brain:plasma = 0.01 ± 0.003; efficacy tested in GBM108), and AZD4547 (brain:plasma = 0.045 ± 0.02; efficacy tested in GBM150). Each of these drugs was effective in relevant GBM PDX flank tumor models with a 27% to 218% prolongation in the median time to exceed their pre-specified endpoint compared to placebo treatment (p≤0.02 for each drug). In contrast, none of these drugs were effective in prolonging survival in the same target-relevant orthotopic tumor models (-6% to 8% extension in median survival; p>0.05 for each drug). Consistent with partial and heterogeneous disruption of the BBB, MALDI-MSI of erlotinib, AZD1775 or SAR405838 distribution within orthotopic tumors demonstrated highly heterogeneous drug levels with large regions within each tumor approaching the low drug levels observed within surrounding normal brain. To further evaluate whether heterogenous drug distribution in orthotopic tumors could account for poor treatment efficacy, GBM108 was transduced with lentiviral constructs encoding for VEGF or empty vector (EV). While both GBM108-sublines were readily detectable with gadolinium-enhanced magnetic resonance imaging (MRI), the GBM108-VEGF tumors had a significantly more disrupted BBB, as evidenced by a more uniform and intense distribution of a brain-impenetrant TexasRed-dextran vascular marker. Similarly, the distribution of SAR405838, measured by MALDI-MSI, was markedly higher and more uniform in the GBM108-VEGF tumors when compared to the GBM108-EV tumors. Enhanced delivery of SAR405838 into orthotopic GBM108-VEGF models translated into a marked enhancement in treatment efficacy in comparison to GBM108-EV with a median survival prolongation of 37 vs. 4 days, respectively (p=0.0055). Collectively, these data highlight the importance of testing novel therapeutic agents in orthotopic tumor models and suggest that limited brain penetration for many molecules may significantly limit their efficacy in brain tumors that have a partially intact BBB. In the face of continued failure to develop effective targeted agents for GBM, these in vivo results highlight the importance of re-evaluating the dogma in neuro-oncology that the BBB is fully disrupted in GBM and, therefore, drug delivery across the BBB is not a major factor limiting treatment efficacy. Citation Format: Jann N. Sarkaria, David Calligaris, Daniel Ma, Karen Parrish, Ann C. Mladek, Janice Laramy, Minjee Kim, Shuangling Zhang, Mark Schroeder, Brett L. Carlson, Katrina Bakken, Aaron Johnson, Nathalie Agar, William Elmquist. The critical importance of the blood-brain barrier in modulating the response to otherwise highly effective targeted therapies in patient-derived orthotopic glioblastoma xenografts. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B25.

Abstract Castration resistant prostate cancer (CRPC) is a deadly disease with a poor prognosis. Treatment options for CRPC patients involve taxanes or newly developed drugs targeting the androgen pathway or androgen synthesis, including CYP17 inhibitors. However, response to therapy varies dramatically among patients, which might be due, in part, to tumor heterogeneity. Therefore, understanding of the genomic landscape of CRPC would be important to help achieve better outcomes by developing personalized therapies. One challenge contributing to our lack of therapies for CRPC is a paucity of clinically relevant animal models predictive of response to therapy in human patients. The Prostate Cancer Medically Optimized Genome Enhanced Therapy (PROMOTE) study is a Mayo Clinic prospective trial designed for patients with metastatic CRPC who are treated with abiraterone acetate, a CYP17 inhibitor, over a 12 week period. Fresh tissue from metastatic lesions, primarily bone metastases, was obtained by needle core biopsy before and 12 weeks after initiating abiraterone acetate treatment. The samples were submitted for DNA and RNA sequencing and were also used to generate patient-derived xenograft (PDX) models. PDX models were developed by injecting biopsy samples subcutaneously or under the renal capsule in male non-obese diabetic (NOD)/severe combined immunodeficient (SCID) or NOD/SCID/IL-2γ-receptor null (NSG) mice implanted with 25mg testosterone pellets at the time of tissue implantation and 2 months later. Baseline samples from 103 unique patients as well as second samples from 61 patients post abiraterone acetate treatment were injected into approximately 600 mice. Of the samples for which pathology is currently available, 31% of the biopsies injected into mice were confirmed to include tumor tissue, which may be compared with a figure of 37.5% of samples sent for sequencing. Thus far, we have established 8 PDX models, four from baseline and four from post treatment samples. Seven models were derived from metastatic bone lesions, and one model from a liver metastasis. The tumor tissue in each model was expanded into a second of generation of mice and harvested when the tumors grew. No tumor was expanded more than four times. Genomic and transcriptomic analysis of xenograft tissue from different “generations” of xenograft expansion is ongoing and will be compared with similar data for the original biopsy. The evaluation of treatment response after exposure of these PDX models to different therapies including CYP19 inhibitors, AR blockers and taxanes is ongoing. These PDX models provide a tool for future drug testing and for studying mechanisms of resistance to therapy in CRPC. Citation Format: Fang Xie, Manish Kohli, Yin Ping, Rafael E. Jimenez, Richard M. Weinshilboum, Liewei Wang. Developing patient derived xenograft (PDX) models for metastatic castration resistant prostate cancer (CRPC) during CYP17 inhibitor therapy. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr A05.

Abstract Clinical genetic testing panels are broadly used to gather information about cancer predisposition in individuals with personal and/or family history of breast cancer. However, the involvement of several of the genes on clinical testing panels in predisposition to breast cancer, such as MRE11A and RAD50, has recently come into question. In addition, accurate risk estimates for breast and other cancer are not well defined for the majority of genes on testing panels. We studied 60,000 women diagnosed with breast cancer who were tested for germline cancer predisposing mutations using hereditary cancer gene panels. Information on personal and family cancer history, age of diagnosis, and ethnicity of patients was obtained from test requisition forms. Greater than 90% met National Comprehensive Cancer Network HBOC testing criteria. To estimate gene-specific risks for breast cancer, case-control analyses were performed comparing the frequencies of pathogenic mutations from Caucasian cancer cases with frequencies from Caucasian, non-Finnish, non-TCGA controls from the Exome Aggregation Consortium (ExAC) database. Mutations were detected in 9% of breast cancer patients. Twelve genes displayed a significant association (p<0.05) with breast cancer. Nine of these genes, including ATM, RAD51D, NF1, and MSH6, were associated with moderate risk (RR>2.0) of breast cancer and three genes (BRCA1, BRCA2, PALB2) were associated with high risk (RR>5.0) of breast cancer. Cumulative age-dependent risk models were developed for each gene. This large clinical testing dataset of 60,000 women with breast cancer provides useful data for many predisposition genes previously lacking risk estimates, and should prove useful for clinical risk management of patients with inherited mutations in these genes. Citation Format: Couch FJ, Hu C, Lilyquist J, Shimelis H, Akinhanmi M, Na J, Polley EC, Hart SN, McFarland R, LaDuca H, Huether R, Goldgar DE, Dolinsky JS. Breast cancer risks associated with mutations in cancer predisposition genes identified by clinical genetic testing of 60,000 breast cancer patients [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr S2-01.

Abstract BACKGROUND: Unique genes and pathways were identified for prognosis on tamoxifen (T, 5 yrs) and prediction on CAF-T vs T in S8814 using whole transcriptome RNA-Seq from archival FFPE tissue. (Albain, et al; Cherbavaz, et al; SABCS 2015) Discovery was robust for early DFS events but sparse for late. The aims of this new analysis were to 1) utilize a new endpoint BCSE for gene discovery of late events, prognosis and prediction and 2) add intronic counts to the previous exonic results to define whole genes impacting on late BCSE. METHODS: Charts of patients (pts) on CAF-T (212) vs T (142) were reviewed to define the BCSE endpoint (local/regional, contralateral, distant). Deaths without BC were treated as competing risks. BCSE models (including metagenes) of late prognosis and prediction used cumulative incidence functions. Consolidated intronic regions counts within genes were added to exonic regions counts. Using these “whole gene” (WG) counts, association of gene expression with time to BCSE was assessed by Cox regression. A multiple WG score (MWGS) for BCSE prognosis beyond 5 yrs (to 12.5 yrs) was constructed and evaluated for 1-3 and 4+ node (N) groups. False discovery rate was controlled at 10%. RESULTS: More exons and WG were discovered for prognosis on T alone over 12.5 yrs with the BCSE endpoint than DFS. For prognosis of late BCSE after 5 yrs, more genes were discovered using WG (n=111) than by exons (n=9). There were significantly fewer genes for late BCSE on CAF-T (8, WG; 0, exons). The functions of WG prognostic for late BCSE were: cell cycle/proliferation-26 genes, chromosome segregation/mitotic spindle-22, DNA repair/maintenance-10, transcriptional/translational control-5, cell adhesion/migration-4, immune-3, diverse/unknown-32 and growth factor/hormone receptor signaling-9 (this group was only found by WGs, not exons). Of these 111 WG, a MWGS prognostic for late BCSE on T used 57 previously discovered genes pre-specified for this analysis. Probability of BCSE beyond 5 yrs for low vs high MWGS was 8% vs 21% in N1-3+ and 17% vs 42% in N4+. Late prognosis on T differed by low vs high risk defined in a metagene model: cumulative BCSE at year 10 was 0% vs 47% (low vs high risk, p=0.001). Prediction of 10-yr incidence of BCSE varied by risk level by treatment in a metagene model: low risk- CAF-T=47%, T=0% (p=0.045); high risk- CAF-T=35%, T=45% (p=0.027). CONCLUSIONS: Gene discovery for prognosis of late BCSE is enhanced with a novel WG transcriptome expression approach. Use of chemotherapy (CT) before T significantly attenuated gene discovery, so that molecular tools for decisions on extending endocrine therapy (ET) may not be reliable in a setting of prior CT. Some pts on ET for 5 yrs may not require either longer ET or CT, given a N+ cohort was defined with no BCSE observed over 12.5 yrs. For prediction of CT benefit, CAF-T appeared to be inferior to T in a low risk metagene model for BCSE. In sum, these results add more evidence that ET alone may be sufficient (perhaps better) in select N+ settings. Validation in SWOG S1007 (RxPONDER) is planned. SUPPORT: NCI CA180888, 180819, 180821, 180820, 180863; in part, Genomic Health, Inc. Citation Format: Albain KS, Crager MR, Barlow WE, Baehner FL, Bergamaschi A, Rae JM, Ravdin PM, Tripathy D, Gralow JR, Livingston RB, Osborne CK, Ingle JN, Pritchard KI, Davidson NE, Carey LA, Cherbavaz DB, Sing AP, Shak S, Hortobagyi GN, Hayes DF. Discovery of molecular predictors of late breast cancer specific events (BCSE) in ER+, node+ breast cancer – new transcriptome expression whole gene analysis of the phase III adjuvant trial SWOG S8814 [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr PD7-07.

Abstract Introduction: The 21-gene Recurrence Score (RS) assay has been shown in retrospective studies to predict benefit of adjuvant chemotherapy (AC) in node positive (N+) breast cancer (BC) patients (pts). This study evaluates the trends and patterns of use of RS assay in N+, ER+/HER2-breast cancer and the impact of RS on decision to use AC in a real-world multi-institutional database. Methods: Pts with T1-T4c, N1mi-N3, ER+/HER2- BC diagnosed between 2010 and 2013, included in the National Cancer Data Base were analyzed. Pts who received neo-AC were excluded. Analyses included Cochrane-Armitage tests for trends and multivariable logistic regression assessing factors influencing RS testing and AC recommendations based on RS. Results: Among 73,049 pts, RS was obtained in 20.6%, increasing from 14.9% in 2010 to 24.4% in 2013 (p<0.001). RS testing was most common in N1mi (43.6%) and N1 (22.0%) and rare in N2/N3 (3.3%) BC. Of the 12,540 BC with quantitative RS results, 61.1% were low RS, 32.3% intermediate RS and 6.6% high RS. AC recommendation was less frequent in pts with RS testing compared to pts not tested (50.4% recommended AC vs 80.9%, p<0.001). In pts with N1mi/N1 BC, recommendation rates for AC were higher with higher RS (see table), however in N2/N3 BC, AC was recommended in the majority (71-88%) regardless of RS. Most pts (>85%) with RS 26-30 or high risk RS were recommended AC regardless of N stage. For pts with low risk RS, recommendation for AC increased significantly with increasing N stage (see table). On multivariable analysis, in pts with low risk RS, AC was more likely to be recommended in those with N1/N2+ stage (OR 2.3 and 9.1 vs N1mi), T2 and T3/T4 tumors (OR 1.3 and 2.2 vs T1 tumors), poorly differentiated tumors (OR 1.6) and younger age (OR 3.4 and 1.7, respectively, for <40 and 40-49 vs 50-59) (all p<0.001). Among pts with RS 18-25, AC was more likely to be recommended in those with higher tumor grade, younger age but the effect of N stage was less pronounced. Histology (IDC vs ILC) did not influence AC recommendation in any RS subset. Path N StageRS Risk GroupLow RiskIntermediate RiskHigh RiskRS<18RS 18-25RS 26-30RS>30N1mi AC No1,854 (75.9%)389 (36.9%)36 (14.6%)16 (7.0%)N1mi AC Yes590 (24.1%)666 (63.1%)210 (85.4%)212 (93.0%)N1 AC No3,000 (60.6%)699 (33.0%)75 (14.8%)33 (6.0%)N1 AC Yes1,954 (39.4%)1,422 (67.0%)431 (85.2%)518 (94.0%)N2/N3 AC No76 (29.0%)17 (16.7%)3 (12.5%)7 (14.9%)N2/N3 AC Yes186 (71.0%)85 (83.3%)21 (87.5%)40 (85.1%)p-value<0.001<0.0010.880.16 Conclusions: RS was obtained in about one fifth of pts with N+ ER+/HER2- BC, predominantly for N1mi and N1 disease. Overall, RS testing decreased frequency of recommendation of AC in N+ BC pts. The RS influenced use of AC particularly in N1mi and N1 pts, likely avoiding overtreatment of those with low risk RS and RS 18-25. Prospective data regarding RS to direct AC in N+ BC are awaited. Citation Format: Peethambaram PP, Hoskin TL, Heins CN, Habermann EB, Boughey JC. How 21-gene recurrence score assay is being used to individualize adjuvant chemotherapy recommendations in ER+/HER2 -node positive breast cancer -A national cancer data base study [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr PD7-05.

Abstract Background: While previous study showed that the enrichment of immune-related gene expression was associated with outcome in HER2+ patients receiving sequential or concurrent trastuzumab (H), stromal tumor infiltrating lymphocytes (sTIL) have not been consistently shown to associate with outcome in this group of patients. Given that TIL scoring may be subjective, we analyzed molecular signatures of different subsets of tumor infiltrating immune cell populations, using NanoStringTM gene expression data to assess molecular TIL (mTIL) signature enrichment and intrinsic subtype as a function of relapse-free survival (RFS). Methods: NanoStringTM technology was used to quantify mRNA in samples from 1,280 patients in N9831, 168 patients in FinHer, and 170 patients in FinXX. In N9831, patients in arm A were treated with chemotherapy alone (AC-T), arm B received chemotherapy followed by sequential H (AC-T-H), and arm C received H concurrently with chemotherapy (AC-TH). In the FinHer trial, H was given concurrently for 9 weeks and either 1 year or 9 weeks in FinXX trial. Cox proportional hazard ratio (HR) was used to determine the association of each gene signature with RFS. Different immune subset signatures, including CD45, B-cells, CD8 T-cells, cytotoxic-cells, and T-cells were analyzed using algorithms developed by NanoString. Results: In N9831, CD45, cytotoxic-cell, and T-cell signatures were significantly associated with improved RFS in patients receiving chemotherapy alone and AC-T-H. However, none of the mTIL signatures were significantly associated with outcome in patients receiving AC-TH. Patients lacking CD45 enrichment had better outcome when H was given concurrently with chemotherapy. The 10-year Kaplan-Meier estimates for RFS in arm B patients with CD45 enrichment or no enrichment were 81.3% and 72.6%, respectively (HR 0.63 [95% CI, 0.42-0.93]; p = 0.02), and in arm C were 83.6% and 79.8%, respectively (HR 0.79, 95%CI 0.49-1.28; p = 0.34). Among patients with HER2-enriched subtype, all of the mTIL signatures were associated with improved RFS in arm A (AC-T) and B (AC-T-H) but remained non-significant in arm C (AC-TH). In patients with luminal subtypes, mTIL signatures were not significantly associated with outcome in patients treated with chemotherapy alone. Similar findings were observed in the FinHer and FinXX trials, in which, none of mTIL signatures were significantly associated with outcome among patients who received H. Conclusion: This analysis sheds light on previous discrepancy between immune-related gene signature and sTIL findings. Our data also suggests that the poor prognosis associated with lack of infiltrating immune cells can be partly overcome by the concomitant administration of H with chemotherapy. mTIL signatures, specifically CD45, cytoxic, and T cells, were prognostically associated with improved outcome in patients receiving chemotherapy without concurrent trastuzumab. Understanding the role of the immune system in response to H will require a higher degree of granularity than can be achieved by histological quantification of TILs. Further studies are needed to validate the significance of mTIL signatures as predictive or prognostic biomarker in HER+ patients. Citation Format: Chumsri S, Serie DJ, Mashadi-Hossein A, Tenner KS, Lauttia SL, Moreno-Aspitia A, McLaughlin SA, Nassar A, Warren S, Danaher P, Colon-Otero G, Lindman H, Joensuu H, Perez EA, Thompson EA. Prognostic value of molecular tumor infiltrating lymphocyte (mTIL) signatures in HER2-positive breast cancer patients in N9831 and FinHer/FinXX trials [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr PD5-06.